Apparatus for treating powdered or granulated substances



Sept. 30, 1969 G. GRUN 3,469,552

' APPARATUS FOR TREATING POWDERBD OR GRANULATED SUBSTANCES Filed July22, 1965 2 Sheets-Sheet 1 Mil a V. L:

G. GRUN Sept. 30, 1969 APPARATUS FOR TREATING POWDERED OR GRANULAIEDSUBSTANCES Filed July 22, 1965 2 Sheets-Sheet 2 United States Patent US.Cl. 11824 9 Claims ABSTRACT OF THE DISCLOSURE Apparatus for treatingsubstances in powder or granulate form with substances in gaseous,liquid or solid form includes an upwardly extending treatment chamberhaving an outlet at its lower end and a separator extending downwardlyfrom the upper end to below the midpoint. The first substances,suspended in a moving air current, are injected into the upper end ofthe separator. The chamber has peripherally spaced apertures in its sidewall above its outlet and below the lower end of the separator, andspray nozzles are each associated with a respective aperture to spraythe gaseous, liquid or solid form substances toward the axis of thechamber. A common annular conduit is connected to the spray nozzles tosupply This application is a continuation-in-part of my copendingapplication Ser. No. 93,011, filed Mar. 1, 1961, for Process forTreating Powdered or Granulated Substances and now abandoned.

This invention relates to apparatus for treating substances in powder orgranulated form and, more particularly, to apparatus of this type inwhich first substances, in powder or granulated form, are treated withsecond active or stabilizing substances, in gaseous, liquid or solidform, by injecting the first substances, suspended in a moving aircurrent, through the upper end of a treatment chamber to spiraldownwardly through the lower portion of the latter and to be admixedwith an upwardly flowing airstream to form a turbulent material-airmixture cloud at a spray region at which second substances are sprayedinto the treatment chamber through a plurality of peripherally spacedopenings in the side wall of the latter with air being aspirated intothe chamber through these openings by the injection action due to suchspraying.

The objectives to be obtained by a treatment of powder or granulatedsubstances with active or stabilizing substances, in gaseous, liquid, orsolid form, may differ. Thus, in producing one product, a requisite isthe complete absence of dust. In another product, it is a requisite thatthe product be soluble in water or other liquid, while in still a thirdproduct, a requisite is that it be miscible with another substance, suchas an odorous substance. Furthermore, still another product may have therequisite that it have grains of a particular size.

Frequently, two or even all of these requirements must be metsimultaneously. It has been found, by tests, that a substantialimprovement of the treated products with respect to meeting theabove-mentioned requirements, a better control of the process, andgreater safety can be achieved by various modifications of the process.and of the apparatus for carrying out the process.

In accordance with one feature of the invention, the treatment chamberis subdivided into a turbulence zone ice and a steadying zone byextending the material separating inlet well into the treatment chamber.

In accordance with another feature of the invention, the spray nozzlemeans is subdivided into a plurality of spray nozzles located outside ofthe treatment chamber. These nozzles are arranged annularly around theoutside of the treatment chamber eac-h adjacent an aperture in the sidewall thereof, these apertures being spaced peripherally around the sidewall of the treatment chamber. The spray nozzles are directed coaxiallythrough the respective apertures and toward the axis of the treatmentchamber.

In accordance with another feature of the invention, two or more annularspray rings are arranged in spaced relation one above the other, andprovided with monitoring and switching means to disconnect all thesupplies simultaneously in the absence of any one of the supplies, sothat there is no after-dripping of liquid from the spray nozzles.

In accordance with still a further feature of the invention, theapparatus is arranged above a drying tower in such a way that thematerial to be treated drops from the treatment chamber directly intothe drying tower. Thus, there is no mechanical stress exerted on thegranular treated material even during the drying process. The treatedparticles always leave the treatment chamber, and pass through thedrying tower, in a suspended, slowly sinking state, and are dried gentlyand then either filled into bags or packed directly beneath the dryingtower.

A further feature of the invention is to improve the dust return andincrease the degree of dust removal, and particularly to provide uniformdust return in the case of sprayed dust. This is efiected by exhaustingthe dusts into dual separator means by means of a medium pressureblower, and injecting the dusts tangentially into the treatment chamber.Adjustment and regulation of a separation eddy at the separator outletsis effected by apertures or bores formed in bends of a suction line,these apertures or bores influencing the separation eddies at theoutlets of the separators. The apertures or bores may be completely orpartly closed by means of a displaceable sleeve of rubber or the like.

In accordance with a further feature of the invention, conveying,weighing, and control devices are arranged in such a way that the powderor granulate substance is emptied into a hopper by means of a remotecontrolled charging balance. This charging balance delivers the drysubstance to the hopper in small quantities or metered amounts, such as5 kg. or less, and these metered amounts or batches are released duringpredetermined time intervals under control of timing relays. Eachmetered amount is supplied to the hopper during a predetermined timeinterval continuing until the next metered amount is ready to bedischarged. This is effected by means of an infinitely variable bucketwheel lock discharging into a distribution worm and through acirculating air-fly wheel with a built-in injector. Thereby the materialis delivered uniformly to a pneumatic conveyor for discharge into thetreatment chamber.

Another object of the invention is to provide an improved apparatus fortreating powdered or granular first substances with gaseous, liquid, orsolid second substances.

A further object of the invention is to provide such an improvedapparatus including a treatment chamber which is subdivided into aturbulence zone and a steadying zone by a material separating inletelement extending downwardly into the treatment chamber.

Yet another object of the invention is to provide such an improvedapparatus in which a plurality of spray nozzles, positioned exteriorlyof the treatment chamber in an annular ring, discharge the secondsubstances into to treatment chamber through peripherally spacedapertures at a spray region within the treatment chamber, these spraynozzles spraying the second substances coaxially of the apertures andtoward the vertical axis of the treatment chamber.

Still another object of the invention is to provide an improvedapparatus of the type just mentioned in which the second substance orsubstances are sprayed into the treatment chamber by means of pluralvertically spaced spray rings.

A still further object of the invention is to provide an improvedapparatus of the type mentioned in which monitoring and switchingdevices are provided to disconnect all the supplies of the secondsubstances simultaneously in the absence of one of the second substancesor of the first subtance.

Yet another object of the invention is to provide an improved apparatusof the type mentioned in which a treatment chamber is positioned above adrying tower in such a manner that the material to be treated drops fromthe treatment chamber directly into the drying tower.

Still a further object of the invention is to provide an improvedapparatus of the type just-mentioned in which the treated particlesleaving the treatment chamber pass through the drying tower in asuspended slowly sinking state whereby they are dried gently.

Another object of the invention is to provide an improved apparatus ofthe type mentioned in which dust return is improved and an increase ofthe degree of dust removal is attained, and in which a uniform dustreturn is supplied with sprayed dusts.

A further object of the invention is to provide an improved apparatus ofthe type mentioned in which the sprayed dusts are exhausted by dualseparator means through the medium of a medium pressure blower, and areinjected tangentially into the treatment chamber.

Still another object of the invention is to provide an improvedapparatus of the type mentioned in which separation eddies at theoutlets of the separators are infiuenced by apertures formed in bends ofthe suction line and controlled by displaceable sleeves of rubber or thelike.

Yet a further object of the invention is to provide an improvedapparatus of the type mentioned including conveying, weighing, andcontrol devices arranged to deliver the substances to be treated asmetered charges each delivered through a predetermind time interval.

Still a further object of the invention is to provide an improvedapparatus of the type mentioned in the preceding paragraph in which themetered charges are fed to an infinitely variable bucket wheel lock andthence into a distribution worm and through a circulating air flywheel,having a built-in injector, which delivers the first substancesuniformly to a pneumatic conveyor for discharge into the treatmentchamber.

In accordance with the mentioned tests, it has further been found thatsimilarity and uniformity of the granular structure depends on how theoriginal product was mixed. These tests have shown that a material mixedin an air mixer, such as shown in German Patent No. 1,152,877, yieldsbetter results with respect to the uniformity of the granular materials.

For an understanding of the principles of the invention, reference ismade to the following description of typical embodiments thereof asillustrated in the accompanying drawings.

In the drawings:

FIG. 1 is a somewhat schematic flow diagram illustrating the invention;

FIG. 2 is a transverse sectional view through a treatment chamber,illustrating the annular arrangement of the spray nozzles about theexterior of the treatment chamber;

FIG. 3 is a partial vertical sectional view through an 4 injectionaperture and illustrating a nozzle, the supply means therefor, the handcontrol valve and the annular conduit;

FIG. 4 illustrates a detail of a flap valve and a slide valvecontrolling flow of material to the dust separators; and

FIG. 5 is a partial diametrical sectional view through the air fly wheeland illustrating the injector flap.

In the process diagram shown in FIG. 1, an air mixer is arranged aheadof the spraying operation proper. In the air mixer 1, the individualcomponents are mixed gently by means of air. The mixing time is 10-20seconds, so that a uniform flow is attained without formation ofbridges, particularly in fine powdered substances. The mixing iseffected in batches, which are then fed to the secondary tank 2. Fromsecondary tank 2, the mixed first substances, of a powdered or granularnature, flow through a coarse dosing lock or sluice 3 into a balance 4.Balance 4 delivers relatively small batches or metered quantities of themixed powdered or granular material into a hopper 5.

Balance 4 is operatively associated with a timing relay which, at theexpiration of a predetermined time interval, initiates tipping of thebalance to deliver a charge into the hopper 5. During the same timeinterval, the material contained in hopper 5 has been fed through aninfinitely variable bucket wheel lock or sluice 6, a worm conveyor 7,and an air flywheel 8 to a pneumatic conveyor or lift 9. Conveyor 9delivers the material into the treatment chamber 11 through a separator10 which discharges the material in the lower portion of the treatmentchamber 11.

The interior of treatment chamber 11 is at a negative pressure of 50-80mm. water column. The conveying air for pneumatic conveyor 9 flowsthrough blower 12, return line 13 and flywheel 8 in a continuous cycle.By observation of a cylinder glass 14, it is possible to regulate thedosing effected by bucket wheel lock 6, having an infinite variabledrive, in such a manner that the material is removed from hopper 5 rightup to the beginning of the next charge from balance 4. Thus, a veryaccurate dosing of the granular or powdered substance is possible,because the weight accuracy from one batch to the next, for example, at5 kg., is determined by the balance. These 5 kg. batches, for example,are distributed throughout a 14 second charging period to the bucketwheel lock 6. A further check is possible by observation of the glasscylinder or inspection glass 15. Any interruptions or gaps in the flowof the powdered or granular material can be equalized by adjustment ofthe infinitely variable drive of the bucket wheel lock 6.

Flywheel 8 has the function of accelerating the material to theconveying speed to avoid a pulsating conveying movement, and also thefunction of reducing the pressure downstream of bucket wheel lock 6, bymeans of the injector 41 illustrated in FIG. 5. These measures arenecessary to insure a trouble-free flow of powdered substances ordifferent quality through bucket wheel lock 6.

The negative pressure produced in treatment chamber 11 by low pressureblower 12, and which can be varied by the regulating flap 16 and theslide valve 16a shown in FIG. 4, causes air to be drawn into treatmentchamber 11 through the outlet 17, this air flowing upwardly through thedescending dry or granular material. By virtue of this, the dry orgranular material is flung upwardly in a sort of central fountain, andforms a cloud into which the spray nozzles 18, arranged as an annularset around the exterior of treatment chamber 11, spray the secondsubstance or liquid in finely dispersed form through peripherally spacedapertures 19 in the side wall of treatment chamber 11, as bestillustrated in FIG. 2. By virtue of this type of spraying, the depositof spray material on the jacket of the treatment chamber is prevented,and a maximum surface contact and uniform distribution of the liquid inthe dry material is Obtained. The spray nozzles 18 direct the liquidspray coaxially of the apertures 19 and toward the vertical axis oftreatment chamber 11.

In the usual manner, the liquid second substance is fed by means ofcharging or dosing piston pumps 29, including the necessary safetyfittings, and is delivered through pressure equalizing tanks 28 to themain access diaphragm valves 24. Downstream of each diaphragm valve 24there is arranged a pressure filter 23 which is directly in front of theassociated annular supply conduit for nozzles 18. The liquid frompressure filter 23 flows, through the annular distribution conduits 22,to the individual nozzle connections 20 which, as best seen in FIG. 3,are each controlled by a hand valve 21. Opposite each inlet duct leadingfrom a pressure filter 23 to a conduit 22, a discharge conduit isconnected to each conduit 22. As best seen in FIG. 1, this dischargeconduit is arched upwardly through 180 of arc and to a height which islower than the height of the individual nozzle connections between theassociated ring conduit 22 and the spray nozzles 18.

Each conduit 22 can be discharged through a diaphragm valve 25 andthrough a lateral oiftake provided with a hand valve 26. Diaphragmvalves 24 and 25 are remote controlled by a suitable control valveassociated with each one thereof. The hand valve 26 serves to regulatethe amount of liquid injected under the required nozzle pressure. Ineffect, the arrangement comprises a return flow arrangement with aspecific inlet pressure and a specific outlet pressure, so that theliquid is sprayed into the treatment chamber 11 under the differentialbetween the inlet pressure and the outlet pressure in the associatedannular supply conduit 22. Preferably, hand valve 26 is designed as aneedle valve, and is arranged to be throttled until the desireddifferential or working pressure has been attained.

The return liquid flows into hoppers 27 from which it may be dischargedinto a suitable tank or returned to the fat tank 30 which is normallycharged from a liquid preparation plant which has not been shown. Thefat tanks 30 are equipped with level indicators, thermostats andautomatic controls. Discharge from the fat tanks 30 is effected by aconduit extending to the suction sides of the charging pumps 29, eachconduit having a hand valve 31 therein.

The air flowing upwardly through treatment chamber 11 from the outlet 17thereof is drawn through separators 33 by a blower 34 which delivers thedust, separated from the air, back to the treatment tank 11. In order tomaintain and adjust the separation to an optimum degree, and to effectefiicient return of the dust through blower 34, a regulating flap isarranged in the suction line. As best illustrtaed in FIG. 4, thisregulating means comprises a pivotal flap valve 16 and a slide valve16a. When flap valve 16 is closed, the air current through treatmentchamber 11 is throttled. The cross sectional area above flap Valve 16aincreases, and can be regulated by slide valve 16a so that theseparators 33 perform an optimum degree of separation. I

The harmful effects of pulsation currents, occurring in the treatmentchamber, on the separation eddies at the outlets of separators 33 areavoided by exhausting, from both separators, some air along with thedust and injecting it by means of the separate high pressure blower 34and the connecting line 36 tangentially into treatment chamber 11 in thesame direction as the dust conveying current. Each separator has aseparate exhaust line, and these two lines are united immediately aheadof blower 34, the lines having bends therein. These bends 'are providedwith several apertures or openings 35 which are normally covered bysleeves 37 of rubber or the like and which are opened only in case ofclogging. Exhaust of air from separators 33 is effected by a suctionblower 32, and the exhaust air is delivered to a pressure filter 38having a collecting hop- 6 per and an outlet duct 39 which may receive acollecting bag 40.

The following examples will illustrate the operation of the invention.Of these examples, the first two relate to the production of a milksubstitute feed which has 17% fat, and of a skim milk feed with up to55% fat.

Example 1 The starting components comprise 30% sprayed skim milk, 30%rolled skim milk, 10% sugar or swelling starch, 10-15 whey powder and 1%vitamins, and these components are thoroughly mixed in air mixer 1 anddischarged, after mixing, into tank 2. The remainder of the startingmixture is fat.

While the mixing of the components is effected in batches, the fat issprayed continuously into the treatment. From tank 1, mixed milk powderflows through bucket wheel lock 3 into balance 4 and is fed throughglass cylinder 14, bucket wheel lock 6, worm conveyor 7, air fly wheel 8and pneumatic conveyor 9 into spreader 10 and thus delivered to thelower part of treatment chamber 11. This is effected continuously andwith a uniform flow delivering a predetermined output to the treatmentchamber 11. After a predetermined time interval of from 10 to 40seconds, the fat is automatically introduced by operating thecorresponding diaphragm valves 24. The end product is discharged fromthe outlet of hopper 17 and filled into bags.

Example 2 In this example, instead of the previously mentionedcomponents, only sprayed skim milk or roller skim milk is used and theseare fed to tank 2 without mixing. The procedure is the same as inExample 1, with the dilference that the air entering through outlet 17from the exterior is cooled to +5 C. by means of a cooling unit. Theamount of heat which must be eliminated by cooling correspondsapproximately to the heat evalved by solidification of the fat. Theextent of cooling influences the fineness of the end product.

Example 3 In this example, powdered substances are treated to increasetheir solubility in the same manner as the powdered skim milkconcentrate is treated in the previous two examples. For example, thisexample may relate to the productions of a mixture for cocoa drinks,such as that known as Kakaotrunk. The components consist of 73.5%powdered sugar, 25% starch, and 1.5% flavor substance. These componentsare homogenously mixed in air mixer 1 and subsequently sprayed with 10%water, which is effected by the spray treatment in treatment chamber 11in the same manner as described in Example 2. The product is then drieddown to 5% by means of a cooling-drying tower arranged beneath the spraytank. The product thus obtained shows a uniform granular structure, hasa loose or porous composition, is highly hygroscopic, and dissolvesrapidly in either water or milk.

Example 4 In this example, easily soluble grain flours are producedusing the same procedure as in Example 3. The difference is that theflour is first reduced to a fineness of 50 and is subsequently subjectedto the spray process by adding about 10% water in chamber 11. Theproduct is finally dried down to a normal moisture of 14% while passingthrough the suspension drier.

What is claimed is:

1. Apparatus for treating first substances, in powder or granulate form,with second active or stabilizing substances, in gaseous, liquid, orsolid form, said apparatus comprising, in combination, an upwardlyextending treatment chamber having an outlet at its lower end; aseparator extending downwardly from the upper end of said chamber tobelow the midpoint thereof; means for injecting the first substances,suspended in a moving air current, into the upper end of said separatorto spiral downwardly from the lower end of said separator through thelower portion of said treatment chamber; a plurality of peripherallyspaced apertures formed in the side wall of said treatment chamber abovesaid outlet and below the lower end of said separator, at a spray regionwithin said chamber; a plurality of spray nozzles positioned exteriorlyof said chamber and each associated with a respective aperture to spraysecond substances coaxially of the associated aperture toward thevertical axis of said chamber; a common annular conduit exteriorlyembracing said chamber and connected to said spray nozzles to supplysecond substances to the latter; and means for effecting a flow of airinto said treatment chamber through said outlet and upwardly throughsaid chamber to form a turbulent material-air mixture cloud at suchspray region, the air flow being so proportioned that only the treatedparticles of the first substance flow to said outlet, with the untreatedparticles being returned to such spray region.

2. Apparatus for treating first substances, in powder or granulate form,with second active or stabilizing substances, in gaseous, liquid, orsolid form, said apparatus comprising, in combination, an upwardlyextending treatment chamber having a conical hopper at its lower endforming an outlet therefor; a separator extending downwardly from theupper end of said chamber to below the midpoint thereof; means forinjecting the first substances, suspended in a moving air current, intothe upper end of said separator to spiral downwardly from the lower endof said separator through the lower portion of said treatment chamber; aplurality of peripherally spaced apertures formed in the side wall ofsaid treatment chamber above said outlet and below the lower end of saidseparator, at a spray region within said chamber; a plurality of spraynozzles positioned exteriorly of said chamber and each associated with arespective aperture to spray second substances coaxially of theassociated aperture toward the vertical axis of said chamber; a commonannular conduit exteriorly embracing said chamber and connected to saidspray nozzles to supply second substances to the latter; and means foreffecting a flow of air into said treatment chamber through said outletand upwardly through said chamber to form a turbulent material-airmixture cloud at such spray region, the air flow being so proportionedthat only the treated particles of the first substance flow to saidoutlet, with the untreated particles being returned to such sprayregion, said apertures being formed above the upper end of said conicalhopper outlet in the lower third of said treatment chamber.

3. Apparatus for treating first substances, in powder or granulate form,with second active or stabilizing substances, in gaseous, liquid, orsolid form, said apparatus comprising, in combination, an upwardlyextending treatment chamber having an outlet at its lower end; aseparator extending downwardly from the upper end of said chamber tobelow the midpoint thereof; means for injecting the first substances,suspended in a moving air current, into the upper end of said separatorto spiral downwardly from the lower end of said separator through thelower portion of said treatment chamber; a plurality of peripherallyspaced apertures formed in the side wall of said treatment chamber abovesaid outlet and below the lower end of said separator, at a spray regionwithin said chamber; a plurality of spray nozzles positioned exteriorlyof said chamber and each associated with a respective aperture to spraysecond substances coaxially of the associated aperture toward thevertical axis of said chamber; a common annular conduit exteriorlyembracing said chamber and connected to said spray nozzles to supplysecond substances to the latter; means for effecting a flow of air intosaid treatment chamber through said outlet and upwardly through saidchamber to form a turbulent material-air mixture cloud at such sprayregion, the air flow being so proportioned that only the treatedparticles of the first substance flow to said outlet, with the untreatedparticles being returned to such spray region; a manually operated valveinterposed between each spray nozzle and said annular conduit; andremote controlled valve means controlling the supply of secondsubstances to said annular conduit.

4. Apparatus for treating first substances, in powder or granulate form,with second active or stabilizing substances, in gaseous, liquid, orsolid form, said apparatus comprising, in combination, an upwardlyextending treatment chamber having an outlet at its lower end; aseparator extending downwardly from the upper end of said chamber tobelow the midpoint thereof; means for injecting the first substances,suspended in a moving air current, into the upper end of said separatorto spiral downwardly from the lower end of said separator through thelower portion of said treatment chamber; a plurality of peripherallyspaced apertures formed in the side wall of said treatment chamber abovesaid outlet and below the lower end of said separator, at a spray regionwithin said chamber; a plurality of spray nozzles positioned exteriorlyof said chamber and each associated with a respective aperture to spraysecond substances coaxially of the associated aperture toward thevertical axis of said chamber; a common annular conduit exteriorlyembracing said chamber and connected to said spray nozzles to supplysecond substances to the latter; means for effecting a flow of air intosaid treatment chamber through said outlet and upwardly through saidchamber to form a turbulent material-air mixture cloud at such sprayregion, the air flow being so proportioned that only the treatedparticles of the first substance flow to said outlet, with the untreatedparticles being returned to such spray region; a supply line connectedto said annular conduit to deliver second substances thereto; manuallyoperable valves, each inter,- posed between said annular conduit and arespective spray nozzle; a remote controlled valve interposed in saidsupply line; a discharge line connected to said annular conduit andextending upwardly and then downwardly through an arc of and a remotecontrolled valve in said discharge line. Y

5. Apparatus for treating first substances, in powder or granulate form,with second active or stabilizing substances, in gaseous, liquid, orsolid form, said apparatus comprising, in combination, an upwardlyextending treatment chamber having an outlet at its lower end; aseparator extending downwardly from the upper end of said chamber tobelow the midpoint thereof; means for injecting the first substances,suspended in a moving air current, into the upper end of said separatorto spiral downwardly from the lower end of said separator through thelower portion of said treatment chamber; a plurality of peripherallyspaced apertures formed in the side wall of said treatment chamber abovesaid outlet and below the lower end of said separator, at a spray regionwithin said chamber; a plurality of spray nozzles positioned exteriorlyof said chamber and each associated with a respective aperture to spraysecond substances coaxially of the associated aperture toward thevertical axis of said chamber; a common annular conduit exteriorlyembracing said chamber and connected to said spray nozzles to supplysecond substances to the latter; means for effecting a flow of air intosaid treatment chamber through said outlet and upwardly through saidchamber to form a turbulent material-air mixture cloud at such sprayregion, the air flow being so proportioned that only the treatedparticles of the first substance flow to said outlet, with the untreatedparticles being returned to such spray region; a supply line connectedto said annular conduit to deliver second substances thereto; manuallyoperable valves, each interposed between said annular conduit and arespective spray nozzle; a remote controlled valve interposed in saidsupply line; a discharge line connected to said annular conduit andextending upwardly and then downwardly through an arc of 180;

a remote controlled valve in said discharge line; and a manual valve insaid discharge line adjustable to set the eifective pressure of thespray from said spray nozzles. 6. Apparatus for treating firstsubstances, in powder or granulate form, with second active orstabilizing substances, in gaseous, liquid, or solid form, saidapparatus comprising, in combination, an upwardly extending treatmentchamber having an outlet at its lower end; a separator extendingdownwardly from the upper end of said chamber to below the midpointthereof; means for injecting the first substances, suspended in a movingair current, into the upper end of said separator to spiral downwardlyfrom the lower end of said separator through the lower portion of saidtreatment chamber; a plurality of peripherally spaced apertures formedin the side wall of said treatment chamber above said outlet and belowthe lower end of said separator, at a spray region within said chamber;a plurality of spray nozzles positioned exteriorly of said chamber andeach associated with a respective aperture to spray second substancescoaxially of the associated aperture toward the vertical axis of saidchamber; a common annular conduit exteriorly embracing said chamber andconnected to said spray nozzles to supply second substances to thelatter; means for effecting a flow of air into said treatment chamberthrough said outlet and upwardly through said chamber to form aturbulent material-air mixture cloud at such spray region, the air flowbeing so proportioned that only the treated particles of the firstsubstance flow to said outlet, with the untreated particles beingreturned to such spray region; an exhaust line extending from the upperend of said chamber exteriorly of said separator; a blower connected tosaid exhaust line and discharging into said chamber at a pointintermediate the upper and lower ends thereof; and a regulating devicein said discharge line in advance of said blower, said regulating de-'vice comprising a flap valve in said discharge line and a slide valveclosing an aperture in said discharge line downstream of said flap valveand in advance of said blower.

7. Apparatus for treating first substances, in powder or granulate form,with second active or stabilizing substances, in gaseous, liquid, orsolid form, said apparatus comprising, in combination, an upwardlyextending treatment chamber having an outlet at its lower end; aseparator extending downwardly from the upper end of said chamber tobelow the midpoint thereof; means for injecting the first substances,suspended in a moving air current, into the upper end of said separatorto spiral downwardly from the lower end of said separator through thelower portion of said treatment chamber; a plurality of peripherallyspaced apertures formed in the side wall of said treatment chamber abovesaid outlet and below the lower end of said separator, at a spray regionwithin said chamber; a plurality of spray nozzles positioned exteriorlyof said chamber and each associated with a respective aperture to spraysecond substances coaxially of the associated aperture toward thevertical axis of said chamber; a common annular conduit exteriorlyembracing said chamber and connected to said spray nozzles to supplysecond substances to the latter; means for effecting a flow of air intosaid treatment chamber through said outlet and upwardly through saidchamber to form a turbulent material-air mixture cloud at such sprayregion, the air flow being so proportioned that only the treatedparticles of the first substance flow to said outlet, with the untreatedparticles being returned to such spray region, a pair of dustseparators; a dust discharge line connecting the upper end of saidchamber, exteriorly of said first mentioned separator, to each of saidsecond mentioned separators; a blower; means separately connecting theoutlets of each of said dust separators to the inlet of said blower; andmeans connecting the outlet of said blower to the interior of saidtreatment chamber intermediate the upper and lower ends thereof todischarge dust and air from said dust separators tangentially into saidtreatment chamber.

8. Apparatus for treating first substances, in powder or granulate form,with second active or stabilizing substances, in gaseous, liquid, orsolid form, said apparatus comprising, in combination, an upwardlyextending treatment chamber having an outlet at its lower end; aseparator extending downwardly from the upper end of said chamber tobelow the midpoint thereof; means for injecting the first substances,suspended in a moving air current, into the upper end of said separatorto spiral downwardly from the lower end of said separator through thelower portion of said treatment chamber; a plurality of peripherallyspaced apertures formed in the side wall of said treatment chamber abovesaid outlet and below the lower end of said separator, at a spray regionwithin said chamber; a plurality of spray nozzles positioned exteriorlyof said chamber and each associated with a respective aperture to spraysecond substances coaxially of the associated aperture toward thevertical axis of said chamber; a common annular conduit exteriorlyembracing said chamber and connected to said spray nozzles to supplysecond substances to the latter; means for elfecting a flow of air intosaid treatment chamber through said outlet and upwardly through saidchamber to form a turbulent material-air mixture cloud at such sprayregion, the air flow being so proportioned that only the treatedparticles of the first substance flow to said outlet, with the untreatedparticles being returned to such spray region; said injecting meansincluding a pneumatic conveyor communicating at one end with the upperend of said separator; balance means effective to deliver measuredbatches of said first substance; and an air fly wheel connected toreceive the batches from said balance means and to deliver a continuousflow of said first substances to the other end of said pneumaticconveyor.

9. Apparatus for treating first substances, in powder or granulate form,with second active or stabilizing substances, in gaseous, liquid, orsolid form, said apparatus comprising, in combination, an upwardlyextending treatment chamber having an outlet at its lower end; aseparator extending downwardly from the upper end of said chamber tobelow the midpoint thereof; means for injecting the first substances,suspended in a moving air current, into the upper end of said separatorto spiral downwardly from the lower end of said separator through thelower portion of said treatment chamber; a plurality of peripherallyspaced apertures formed in the side wall of said treatment chamber abovesaid outlet and below the lower end of said separator, at a spray regionwithin said chamber; a plurality of spray nozzles positioned exteriorlyof said chamber and each associated with a respective aperture to spraysecond substances coaxially of the associated aperture toward thevertical axis of said chamber; a common annular conduit exteriorlyembracing said chamber and connected to said spray nozzles to supplysecond substances to the latter; means for effecting a flow of air intosaid treatment chamber through said outlet and upwardly through saidchamber to form a turbulent material-air mixture cloud at such sprayregion, the air flow being so proportioned that only the treatedparticles of the first substance flow to said outlet, with the untreatedparticles being returned to such spray region; said injecting meansincluding a pneumatic conveyor communicating at one end with the upperend of said separator; balance means effective to deliver measuredbatches of said first substance; an air fly wheel connected to receivethe batches from said balance means and to deliver a continuous flow ofsaid first substance to the other end of said pneumatic conveyor; saidinjection means further including a hopper for supplying material tosaid balance means; a worm conveyor extending between said balance meansand said air fly 11 12 wheel; and an injectqr at the outlet of said airfly wheel WALTER A. SCHEEL, Primary Examiner 1n commun1cat1on w1th sa1dpneumauc conveyor. JOHN P. MCINTOSH, AssistantlExaminer References CitedI UNITED STATES PATENTS 5 1,854,100 4/1932 Brito 118303X 2,071,8462/1931 Lamb et a1. 11s 303 2,594,469 4/1952 Mahoney 117-100

